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Merge pull request #165 from prometheus/api 

Add initial HTTP API v1 package
This commit is contained in:
Fabian Reinartz 2015-08-19 19:06:35 +02:00
parent 8f8d39e0fd 2aae630ba8
commit 223315ae31
2 changed files with 815 additions and 0 deletions
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362
api/prometheus/api.go Normal file
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// Copyright 2015 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package prometheus provides bindings to the Prometheus HTTP API:
// http://prometheus.io/docs/querying/api/
package prometheus
import (
"encoding/json"
"fmt"
"io/ioutil"
"net"
"net/http"
"net/url"
"path"
"strconv"
"strings"
"time"
"github.com/prometheus/common/model"
"golang.org/x/net/context"
)
const (
statusAPIError = 422
apiPrefix = "/api/v1"
epQuery = "/query"
epQueryRange = "/query_range"
epLabelValues = "/label/:name/values"
epSeries = "/series"
)
type ErrorType string
const (
// The different API error types.
ErrBadData ErrorType = "bad_data"
ErrTimeout = "timeout"
ErrCanceled = "canceled"
ErrExec = "execution"
ErrBadResponse = "bad_response"
)
// Error is an error returned by the API.
type Error struct {
Type ErrorType
Msg string
}
func (e *Error) Error() string {
return fmt.Sprintf("%s: %s", e.Type, e.Msg)
}
// CancelableTransport is like net.Transport but provides
// per-request cancelation functionality.
type CancelableTransport interface {
http.RoundTripper
CancelRequest(req *http.Request)
}
var DefaultTransport CancelableTransport = &http.Transport{
Proxy: http.ProxyFromEnvironment,
Dial: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).Dial,
TLSHandshakeTimeout: 10 * time.Second,
}
// Config defines configuration parameters for a new client.
type Config struct {
// The address of the Prometheus to connect to.
Address string
// Transport is used by the Client to drive HTTP requests. If not
// provided, DefaultTransport will be used.
Transport CancelableTransport
}
func (cfg *Config) transport() CancelableTransport {
if cfg.Transport == nil {
return DefaultTransport
}
return cfg.Transport
}
type Client interface {
url(ep string, args map[string]string) *url.URL
do(context.Context, *http.Request) (*http.Response, []byte, error)
}
// New returns a new Client.
func New(cfg Config) (Client, error) {
u, err := url.Parse(cfg.Address)
if err != nil {
return nil, err
}
u.Path = apiPrefix
return &httpClient{
endpoint: u,
transport: cfg.transport(),
}, nil
}
type httpClient struct {
endpoint *url.URL
transport CancelableTransport
}
func (c *httpClient) url(ep string, args map[string]string) *url.URL {
p := path.Join(c.endpoint.Path, ep)
for arg, val := range args {
arg = ":" + arg
p = strings.Replace(p, arg, val, -1)
}
u := *c.endpoint
u.Path = p
return &u
}
func (c *httpClient) do(ctx context.Context, req *http.Request) (*http.Response, []byte, error) {
type roundTripResponse struct {
resp *http.Response
err error
}
rtchan := make(chan roundTripResponse, 1)
go func() {
resp, err := c.transport.RoundTrip(req)
rtchan <- roundTripResponse{resp: resp, err: err}
close(rtchan)
}()
var resp *http.Response
var err error
select {
case rtresp := <-rtchan:
resp, err = rtresp.resp, rtresp.err
case <-ctx.Done():
// Cancel request and wait until it terminated.
c.transport.CancelRequest(req)
resp, err = (<-rtchan).resp, ctx.Err()
}
defer func() {
if resp != nil {
resp.Body.Close()
}
}()
if err != nil {
return nil, nil, err
}
var body []byte
done := make(chan struct{})
go func() {
body, err = ioutil.ReadAll(resp.Body)
close(done)
}()
select {
case <-ctx.Done():
err = resp.Body.Close()
<-done
if err == nil {
err = ctx.Err()
}
case <-done:
}
return resp, body, err
}
// apiClient wraps a regular client and processes successful API responses.
// Successful also includes responses that errored at the API level.
type apiClient struct {
Client
}
type apiResponse struct {
Status string `json:"status"`
Data json.RawMessage `json:"data"`
ErrorType ErrorType `json:"errorType"`
Error string `json:"error"`
}
func (c apiClient) do(ctx context.Context, req *http.Request) (*http.Response, []byte, error) {
resp, body, err := c.Client.do(ctx, req)
if err != nil {
return resp, body, err
}
code := resp.StatusCode
if code/100 != 2 && code != statusAPIError {
return resp, body, &Error{
Type: ErrBadResponse,
Msg: fmt.Sprintf("bad response code %d", resp.StatusCode),
}
}
var result apiResponse
if err = json.Unmarshal(body, &result); err != nil {
return resp, body, &Error{
Type: ErrBadResponse,
Msg: err.Error(),
}
}
if (code == statusAPIError) != (result.Status == "error") {
err = &Error{
Type: ErrBadResponse,
Msg: "inconsistent body for response code",
}
}
if code == statusAPIError && result.Status == "error" {
err = &Error{
Type: result.ErrorType,
Msg: result.Error,
}
}
return resp, []byte(result.Data), err
}
// Range represents a sliced time range.
type Range struct {
// The boundaries of the time range.
Start, End time.Time
// The maximum time between two slices within the boundaries.
Step time.Duration
}
// queryResult contains result data for a query.
type queryResult struct {
Type model.ValueType `json:"resultType"`
Result interface{} `json:"result"`
// The decoded value.
v model.Value
}
func (qr *queryResult) UnmarshalJSON(b []byte) error {
v := struct {
Type model.ValueType `json:"resultType"`
Result json.RawMessage `json:"result"`
}{}
err := json.Unmarshal(b, &v)
if err != nil {
return err
}
switch v.Type {
case model.ValScalar:
var sv model.Scalar
err = json.Unmarshal(v.Result, &sv)
qr.v = &sv
case model.ValVector:
var vv model.Vector
err = json.Unmarshal(v.Result, &vv)
qr.v = vv
case model.ValMatrix:
var mv model.Matrix
err = json.Unmarshal(v.Result, &mv)
qr.v = mv
default:
err = fmt.Errorf("unexpected value type %q", v.Type)
}
return err
}
// QueryAPI provides bindings the Prometheus's query API.
type QueryAPI interface {
// Query performs a query for the given time.
Query(ctx context.Context, query string, ts time.Time) (model.Value, error)
// Query performs a query for the given range.
QueryRange(ctx context.Context, query string, r Range) (model.Value, error)
}
// NewQueryAPI returns a new QueryAPI for the client.
func NewQueryAPI(c Client) QueryAPI {
return &httpQueryAPI{client: apiClient{c}}
}
type httpQueryAPI struct {
client Client
}
func (h *httpQueryAPI) Query(ctx context.Context, query string, ts time.Time) (model.Value, error) {
u := h.client.url(epQuery, nil)
q := u.Query()
q.Set("query", query)
q.Set("time", ts.Format(time.RFC3339Nano))
u.RawQuery = q.Encode()
req, _ := http.NewRequest("GET", u.String(), nil)
_, body, err := h.client.do(ctx, req)
if err != nil {
return nil, err
}
var qres queryResult
err = json.Unmarshal(body, &qres)
return model.Value(qres.v), err
}
func (h *httpQueryAPI) QueryRange(ctx context.Context, query string, r Range) (model.Value, error) {
u := h.client.url(epQueryRange, nil)
q := u.Query()
var (
start = r.Start.Format(time.RFC3339Nano)
end = r.End.Format(time.RFC3339Nano)
step = strconv.FormatFloat(r.Step.Seconds(), 'f', 3, 64)
)
q.Set("query", query)
q.Set("start", start)
q.Set("end", end)
q.Set("step", step)
u.RawQuery = q.Encode()
req, _ := http.NewRequest("GET", u.String(), nil)
_, body, err := h.client.do(ctx, req)
if err != nil {
return nil, err
}
var qres queryResult
err = json.Unmarshal(body, &qres)
return model.Value(qres.v), err
}

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api/prometheus/api_test.go Normal file
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// Copyright 2015 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package prometheus
import (
"encoding/json"
"fmt"
"net/http"
"net/url"
"reflect"
"testing"
"time"
"github.com/prometheus/common/model"
"golang.org/x/net/context"
)
func TestConfig(t *testing.T) {
c := Config{}
if c.transport() != DefaultTransport {
t.Fatalf("expected default transport for nil Transport field")
}
}
func TestClientURL(t *testing.T) {
tests := []struct {
address string
endpoint string
args map[string]string
expected string
}{
{
address: "http://localhost:9090",
endpoint: "/test",
expected: "http://localhost:9090/test",
},
{
address: "http://localhost",
endpoint: "/test",
expected: "http://localhost/test",
},
{
address: "http://localhost:9090",
endpoint: "test",
expected: "http://localhost:9090/test",
},
{
address: "http://localhost:9090/prefix",
endpoint: "/test",
expected: "http://localhost:9090/prefix/test",
},
{
address: "https://localhost:9090/",
endpoint: "/test/",
expected: "https://localhost:9090/test",
},
{
address: "http://localhost:9090",
endpoint: "/test/:param",
args: map[string]string{
"param": "content",
},
expected: "http://localhost:9090/test/content",
},
{
address: "http://localhost:9090",
endpoint: "/test/:param/more/:param",
args: map[string]string{
"param": "content",
},
expected: "http://localhost:9090/test/content/more/content",
},
{
address: "http://localhost:9090",
endpoint: "/test/:param/more/:foo",
args: map[string]string{
"param": "content",
"foo": "bar",
},
expected: "http://localhost:9090/test/content/more/bar",
},
{
address: "http://localhost:9090",
endpoint: "/test/:param",
args: map[string]string{
"nonexistant": "content",
},
expected: "http://localhost:9090/test/:param",
},
}
for _, test := range tests {
ep, err := url.Parse(test.address)
if err != nil {
t.Fatal(err)
}
hclient := &httpClient{
endpoint: ep,
transport: DefaultTransport,
}
u := hclient.url(test.endpoint, test.args)
if u.String() != test.expected {
t.Errorf("unexpected result: got %s, want %s", u, test.expected)
continue
}
// The apiClient must return exactly the same result as the httpClient.
aclient := &apiClient{hclient}
u = aclient.url(test.endpoint, test.args)
if u.String() != test.expected {
t.Errorf("unexpected result: got %s, want %s", u, test.expected)
}
}
}
type testClient struct {
*testing.T
ch chan apiClientTest
req *http.Request
}
type apiClientTest struct {
code int
response interface{}
expected string
err *Error
}
func (c *testClient) url(ep string, args map[string]string) *url.URL {
return nil
}
func (c *testClient) do(ctx context.Context, req *http.Request) (*http.Response, []byte, error) {
if ctx == nil {
c.Fatalf("context was not passed down")
}
if req != c.req {
c.Fatalf("request was not passed down")
}
test := <-c.ch
var b []byte
var err error
switch v := test.response.(type) {
case string:
b = []byte(v)
default:
b, err = json.Marshal(v)
if err != nil {
c.Fatal(err)
}
}
resp := &http.Response{
StatusCode: test.code,
}
return resp, b, nil
}
func TestAPIClientDo(t *testing.T) {
tests := []apiClientTest{
{
response: &apiResponse{
Status: "error",
Data: json.RawMessage(`null`),
ErrorType: ErrBadData,
Error: "failed",
},
err: &Error{
Type: ErrBadData,
Msg: "failed",
},
code: statusAPIError,
expected: `null`,
},
{
response: &apiResponse{
Status: "error",
Data: json.RawMessage(`"test"`),
ErrorType: ErrTimeout,
Error: "timed out",
},
err: &Error{
Type: ErrTimeout,
Msg: "timed out",
},
code: statusAPIError,
expected: `test`,
},
{
response: "bad json",
err: &Error{
Type: ErrBadResponse,
Msg: "bad response code 400",
},
code: http.StatusBadRequest,
},
{
response: "bad json",
err: &Error{
Type: ErrBadResponse,
Msg: "invalid character 'b' looking for beginning of value",
},
code: statusAPIError,
},
{
response: &apiResponse{
Status: "success",
Data: json.RawMessage(`"test"`),
},
err: &Error{
Type: ErrBadResponse,
Msg: "inconsistent body for response code",
},
code: statusAPIError,
},
{
response: &apiResponse{
Status: "success",
Data: json.RawMessage(`"test"`),
ErrorType: ErrTimeout,
Error: "timed out",
},
err: &Error{
Type: ErrBadResponse,
Msg: "inconsistent body for response code",
},
code: statusAPIError,
},
{
response: &apiResponse{
Status: "error",
Data: json.RawMessage(`"test"`),
ErrorType: ErrTimeout,
Error: "timed out",
},
err: &Error{
Type: ErrBadResponse,
Msg: "inconsistent body for response code",
},
code: http.StatusOK,
},
}
tc := &testClient{
T: t,
ch: make(chan apiClientTest, 1),
req: &http.Request{},
}
client := &apiClient{tc}
for _, test := range tests {
tc.ch <- test
_, body, err := client.do(context.Background(), tc.req)
if test.err != nil {
if err == nil {
t.Errorf("expected error %q but got none", test.err)
continue
}
if test.err.Error() != err.Error() {
t.Errorf("unexpected error: want %q, got %q", test.err, err)
}
continue
}
if err != nil {
t.Errorf("unexpeceted error %s", err)
continue
}
want, got := test.expected, string(body)
if want != got {
t.Errorf("unexpected body: want %q, got %q", want, got)
}
}
}
type apiTestClient struct {
*testing.T
curTest apiTest
}
type apiTest struct {
do func() (interface{}, error)
inErr error
inRes interface{}
reqPath string
reqParam url.Values
reqMethod string
res interface{}
err error
}
func (c *apiTestClient) url(ep string, args map[string]string) *url.URL {
u := &url.URL{
Host: "test:9090",
Path: apiPrefix + ep,
}
return u
}
func (c *apiTestClient) do(ctx context.Context, req *http.Request) (*http.Response, []byte, error) {
test := c.curTest
if req.URL.Path != test.reqPath {
c.Errorf("unexpected request path: want %s, got %s", test.reqPath, req.URL.Path)
}
if req.Method != test.reqMethod {
c.Errorf("unexpected request method: want %s, got %s", test.reqMethod, req.Method)
}
b, err := json.Marshal(test.inRes)
if err != nil {
c.Fatal(err)
}
resp := &http.Response{}
if test.inErr != nil {
resp.StatusCode = statusAPIError
} else {
resp.StatusCode = http.StatusOK
}
return resp, b, test.inErr
}
func TestAPIs(t *testing.T) {
testTime := time.Now()
client := &apiTestClient{T: t}
queryApi := &httpQueryAPI{
client: client,
}
doQuery := func(q string, ts time.Time) func() (interface{}, error) {
return func() (interface{}, error) {
return queryApi.Query(context.Background(), q, ts)
}
}
doQueryRange := func(q string, rng Range) func() (interface{}, error) {
return func() (interface{}, error) {
return queryApi.QueryRange(context.Background(), q, rng)
}
}
queryTests := []apiTest{
{
do: doQuery("2", testTime),
inRes: &queryResult{
Type: model.ValScalar,
Result: &model.Scalar{
Value: 2,
Timestamp: model.TimeFromUnix(testTime.Unix()),
},
},
reqMethod: "GET",
reqPath: "/api/v1/query",
reqParam: url.Values{
"query": []string{"2"},
"time": []string{testTime.Format(time.RFC3339Nano)},
},
res: &model.Scalar{
Value: 2,
Timestamp: model.TimeFromUnix(testTime.Unix()),
},
},
{
do: doQuery("2", testTime),
inErr: fmt.Errorf("some error"),
reqMethod: "GET",
reqPath: "/api/v1/query",
reqParam: url.Values{
"query": []string{"2"},
"time": []string{testTime.Format(time.RFC3339Nano)},
},
err: fmt.Errorf("some error"),
},
{
do: doQueryRange("2", Range{
Start: testTime.Add(-time.Minute),
End: testTime,
Step: time.Minute,
}),
inErr: fmt.Errorf("some error"),
reqMethod: "GET",
reqPath: "/api/v1/query_range",
reqParam: url.Values{
"query": []string{"2"},
"start": []string{testTime.Add(-time.Minute).Format(time.RFC3339Nano)},
"end": []string{testTime.Format(time.RFC3339Nano)},
"step": []string{time.Minute.String()},
},
err: fmt.Errorf("some error"),
},
}
var tests []apiTest
tests = append(tests, queryTests...)
for _, test := range tests {
client.curTest = test
res, err := test.do()
if test.err != nil {
if err == nil {
t.Errorf("expected error %q but got none", test.err)
continue
}
if err.Error() != test.err.Error() {
t.Errorf("unexpected error: want %s, got %s", test.err, err)
}
continue
}
if err != nil {
t.Errorf("unexpected error: %s", err)
continue
}
if !reflect.DeepEqual(res, test.res) {
t.Errorf("unexpected result: want %v, got %v", test.res, res)
}
}
}